RFC 3286 (rfc3286) - Page 2 of 10
An Introduction to the Stream Control Transmission Protocol (SCTP)
Alternative Format: Original Text Document
RFC 3286 SCTP Overview May 2002 2. Basic SCTP Features SCTP is a unicast protocol, and supports data exchange between exactly 2 endpoints, although these may be represented by multiple IP addresses. SCTP provides reliable transmission, detecting when data is discarded, reordered, duplicated or corrupted, and retransmitting damaged data as necessary. SCTP transmission is full duplex. SCTP is message oriented and supports framing of individual message boundaries. In comparison, TCP is byte oriented and does not preserve any implicit structure within a transmitted byte stream without enhancement. SCTP is rate adaptive similar to TCP, and will scale back data transfer to the prevailing load conditions in the network. It is designed to behave cooperatively with TCP sessions attempting to use the same bandwidth. 3. SCTP Multi-Streaming Feature The name Stream Control Transmission Protocol is derived from the multi-streaming function provided by SCTP. This feature allows data to be partitioned into multiple streams that have the property of independently sequenced delivery, so that message loss in any one stream will only initially affect delivery within that stream, and not delivery in other streams. In contrast, TCP assumes a single stream of data and ensures that delivery of that stream takes place with byte sequence preservation. While this is desirable for delivery of a file or record, it causes additional delay when message loss or sequence error occurs within the network. When this happens, TCP must delay delivery of data until the correct sequencing is restored, either by receipt of an out-of-sequence message, or by retransmission of a lost message. For a number of applications, the characteristic of strict sequence preservation is not truly necessary. In telephony signaling, it is only necessary to maintain sequencing of messages that affect the same resource (e.g., the same call, or the same channel). Other messages are only loosely correlated and can be delivered without having to maintain overall sequence integrity. Another example of possible use of multi-streaming is the delivery of multimedia documents, such as a web page, when done over a single session. Since multimedia documents consist of objects of different sizes and types, multi-streaming allows transport of these components Ong & Yoakum Informational
